This invention relates to component placement.
In populating printed circuit boards (PCB), components are placed in solder paste on a board using high-speed automated equipment. The equipment typically includes a table capable of precise movement in an x-y plane and devices for placing components on PCBs that are held on the table using fixtures. One such component placement machine is the Fuji CP642 Chip Placer sold by Fuji North America, Vernon Hills, Ill.
Referring to FIG. 1, one way to hold a PCB 10 for placement of components 12 on a primary side 13 of the PCB is to support the board 10 on a secondary side 14 using an array of height-adjustable pins 15 attached to a phenolic plate 16 that is mounted on the x-y table 17 of the component placement machine (not shown).
The primary side of a PCB is the side on which components are placed first. The secondary side of a board may receive additional components after components on the primary side have been mounted.
Referring to FIG. 2, the height of each pin 15 may be adjusted independently during set-up before a manufacturing run. Typically, each pin is adjusted by hand and, as a result, the height of a given pin 15 may be adjusted incorrectly leaving gaps 18. The resulting inconsistent support may cause bending of board 10 and lead to damage of both PCB 10 and placed components 12, increasing manufacturing costs. When a pin is too high, the component placement machine may damage (e.g., crack) components 12 or PCB 10. When a pin is too low, a component may be seated improperly in the solder paste or not be placed at all. Setting the pins is time consuming.